Optical system for projectors



Dec. l2, 1933. wl L. WRIGHT OPTICAL SYSTEM FOR PROJECTORS Filed March 2, 1951 )ununuuuunnuuunnunnnunnuuuul Patented uvDec. l2, 1933 1i fum-TEDSTTES '-Calif., a corporation of'v California Thisinvention `has .to :do with motion :pic- `tureapparatus and has particular reference to an: optical systemA for projectors. It is a general `object of,` the presentinventionto provide; 'a 5 simple, effective, and practicalvoptical system for usein projectinga pluralityfof*pictures'onto a Vscreen simultaneously and in register.V

In f accordance with certain, methods of "pro- `ducing motion picturesriny color,"` a film is pro- .10 duced carrying series of images of aY subject, each Vseries of imagescomprising a plurality, usually three images, arrangedl along. the'lm, each image of a series being of a different color value `of the subject. .My; present invention is notspeciflcally concerned withsthe production of the film referred to; but is concerned With'thepmjectionof suchfllm to obtain projected images of the several pictures lof aserie's in registeron a screen.A `For, purpose `vof example I 'will refer to amotionpicture film in 'which each series. of v pictures comprises three .pictures arrangedside by side alongY the film, eachlpicture being Aof a different color valueofthe subject, the vseveral pictures having been taken simultaneously and from 4a single` point' of vision soV that they will register to form -a Aperfectpicture on* a' screen wheniprojected -onto `the screen in register.` .It isV an objectpithe present invention to provide ari optical `system forrprojecting a film" of type practicalfor commercialpuse-'can befused.

The system of the present inventionv may be carl 1 frying the images of theend pictures Vof theserles ried out with a lensizof -about the same size` and constructioiras` Vis Yordinarily employed Vin vthe projection of motion'pictures. y 1

Another objectV of'this invention is to provide anY optical system ofthe-character mentioned which is withoutmirrorsiorfreflectorsliable to "create distortion or variation inthe projected tioned* in which 1 the shafts ofH light passingthrough 'theroutermost pictures ortend pictures of the series ofrpictureson the'lmare directed 'lensare deflnitelyvsparatd' from-the'shaft of the middle *picture to be individually acted'wupon by optical elements in frontof the'projectio'n lens. The various objects and features'of'my in- Lvalues ofthesubject..V The l arrangement of the the charactenmentioned, ywhich system. requires` al short distance beyond the film, a projection len'slpassing the severalf shafts carrying the Aimages from .theilm, means 14 beyond the proand to `neutralize distortion created byL the inwardly'by'prisms so-fthat the light from the' A'end pictures after passing through the projection vention will be Vand more fully understood from the following detaileddescriptlon of a typical. form .fand application of the invention,

The `present invention may be V'employed to handle film ofvarious forms or types, but is particularly suited to handling a lm F carryf ing a plurality of series of pictures of a subject, Veach series including pictures A, B, andV C, each lLV of different 'color Valuesrof-a subject: for in- -stanc'egthefpicture A may be of theorange values.

of the subject,- thepicture B ofthe violet values `of'lthe subject, and the picture C of the green 75 pictures of eachseries and the manner in Awhich theuseveral series of 'images occur on the film are illustratedin Figi 2. The several images or pictures vofheachiseries arev alike except for their being of different color values of a subject,ri. e.,

the severalpict'ures' of each series show. the subject'inexactly the `same position and are taken Vfrom the'same anglegorV point of vision;

'Iheoptical system provided by the present inventionvinclu'des, generally, a source of light `10,.a`..fl1m gate 11 for holding the film F in the A4path of light-from the source l0 so that light is simultaneously projected through Vthe several pictures ofa series; means 12 intercepting the -lightfpassing throughthe end pictures of the seriesfto deflect the'light so that the shafts carconverge to intersect the shaft carrying the im- 'ageof thev center pictureof the series at a point jection lens 13 for passing the light deflected by the means 12 to correct the direction of travel 100 means' 12, and various other elements the details ofjwhich'willbe hereinafter described.

' The source of light 10 may' be a single source of 1igh1;,-or it may befa piurauty of individual s ourcesoperating to direct three shafts of light `through the film F heldin the gate Yl1. The axesofthelseveral. shafts are designated in the v Several axes X, Y, and Z may occur 1n one large lio shaft of light which is directed onto the film F at the gate 11.

The film gate 11 may be of any suitable construction which will properly hold and guide the film F so that it intersects the light from the source 10. In the drawing, the means 11 is shown as includingfan aperture plate -15 ihaving an aperture V16 of suchfsize and proportions .ais'to allow the passage of light through the several pictures A, B, and C of a series of pictures on the film F. .Y

The means 12 operates todeflectqnly the light passing through the end pictures, that is, the pictures A and C, of the .series v of I )Ticwrtures ,entire film, so that they converge ftojfnterse e of light passing through the center-picture B at a point a short distance `beyond the film F,

I provide two prisms 17 in the path ofthe shaftsY of light passing through the picturesA and spaced apart so that they do not interfere withthe passage of the shaft of light-'passing ';th`e'picture"B. The prisms 17 parearranged and Lareof such-proportions esto deflect the shafts -of :light passingethe-pictures A andC the' desired amount', preferably Lanamount such as to cause these shafts to :intersectk .the ,shaft of light passing the picture B at or about the center Vofthe projection Yiena 13. The diagram Fig. I' illustrates vlthe manner inwhich the fprismsl'l deflect the shafts of light passing the pictures A and' C so that4 they converge -andfintersect the n shaft of `light .passing rthe picture B.

The projection lens 13 is located at'th'e -proper distance beyond v:the hlm AF. In the preferred form ,of the invention, the system. is I designed so that the projectionv lens V13 occurs vat the point t of intersectionof the several V,shafts l 0f light passing the pictures of the `film ',Ihe projec- V ation lens may be ,cfa type ,or ydesign similar to Vthat ordinarily emplc'iyed in the projection 4of rnotionpictures.-v l- At a suitable distang"beyond` the projection lens 13 yI provide themeans 14 whichoperates `to intercept the shafts of lightfhandledby .the

prisms l'lof the means l2 Vto deect'sa'id shafts so thatthey extend substantially parallelY with the shaft passed by the center pictures-Bin order that the several wshaftsrmay fall upon a screen in register. 'Ihe means 14 includes a prism 18 arranged tointercept each shaft of 'light deflected by the means 12. The prismsl of the means 14 are located somewhat ahead of r,the projection lens 13 and' are spaced apart S0. that the shaft of light passed through the plcanceris provided. between the prisms handling `the shaft of light passingk the picture C. In

practice, the prisms 17 are mounted inthe' apparatus so that they mayV be suitably shifted or adjustedas indicated by .the arrows 1-t0 prcperf .1y position them in the of :liebt which they mtercept it having been ,found-that. by, suitably shifting or ,adjusting ,thema of the prisms,

meses. 0f the pictures A ands? be ily brought .inte resister en. a ,Screen with the ,image `of thepicturc 15.*.V .In .the case of ,a film? .carrying .black and Awhite images. of the different Color values of a subject,

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for instance, the orange,'violet, and green values of the subject, it is desired to provide means for chromatically influencing the several shafts of light. Color filters 20, 21, and 22 may be inserted in the system at a suitable point. I have illustrated color filters located immediately beyond the prisms 118.y A-In acase where the pictures A, B, and are ,of .the orange, violet, and green values of a subject, respectively, the filters 22, 21, and 20 will be orange, violet, and green, respectively.

, It is to be understood that the apparatus may include the A various elements common to projectors, vfor instance, it may include a shutter 25 `-forin terrnittently interrupting the light, a movefgnentspmket :2,6, or the like, for intermittently advancing the fllmthrough the gate l1, a movement mechanism 27, etc. In the diagram Fig. 1, I have villustrated a `barrel type shutter 25 interpos e l between the source of light 10 and gate 11 which carries the film F. I have shown a move- -ment mechanism 27 arranged to drive the feed sprocket y26 and alsooperatingthe drive shaft 28 `of the shutter. It will be understood, 'of course, that the feed sprocketand shutter are related through V,the movement mechanism or through'l100 other suitable means so that they operate in proper synchronismxto ycause the light to be cut off during movement ofthe film and allowed to' project V.through the system only when the film is stationary inthe gate 11.

From the Aforegoing .description it will be apparent that I have provided an optical system that is Vextremely simple and in which the'llght is handled so that theV images are notwdistorted `butlareV brought into register on a screen.

Y Having described only a typical preferred form i of my invention, I do not wish'to limit myself to the specific .details set forth, but wish to'reserve `to myself any changes or variations that may appear to those skilled in the art or fall Within the 11u' scope of the following claims:

Having describedmy invention, I'claim:

l. Apparatus for projecting a series of pictures occurring longitudinally on a lm including, meansY projecting shafts of light through the several pictures of the series substantially perpendicularlyto plane of the film, means receiving the I shafts that have been passed bythe end pictures of .the series and directing-them inwardly to intersect the shaft passed by the middle picture of the series, a single projectionflens passing the several shafts passed by the film, the second mentioned means being between the lm and lens, 'and means beyond the lens directing'the shafts passedby the end pictures of the series Yonto a screen in register with the shaft passed by the middle picture of the series.

2. Apparatus for projecting a series of pictures yoccurring longitudinallyv on a. film including, means projecting shafts of light through theseveral pictures of theseries substantially perpendic- `ularl'y to the plane Aof the lm, a pair of spaced prismsreceiv'ing the jshafts that have been passed by the end pictures of the series and vdirecting them inwardly tolntersect the shaft passed by the middlel picture of the series, a single projection lens passing the several shafts passed by the film, thevsaid prisms beingA located between the lm and lens., and a pair of spaced prisms beyond the lens4 directing the shafts passed by the end pictures of the seriesonto e screen in resister with Athehslulift passedbythe middle picture ofthe Series, Qfbtoth'peirs beingl spaced apart `S9 that .the pessedrby the middle picture is not interrupted. f

8'. Apparatus for projecting a sex-ies of pictures occurring longitudinally on a film including, a gate holding the film, means projecting' shafts of iight vthrough the several pictures of a series.

the light shafts passing the shafts of light at a. point where they are close together, the said pair of prisms being located between the gate and lens, a pair of spaced prisms beyond the lens spaced to pass the shaft passed by the middle picture directly onto a screen and intercepting the shafts passed by the end pictures of the series to direct them onto a screen in register with the shaft passed by the middle picture, and color filters in the paths of the several shafts of light adjacent the last mentioned prisms.

WALTER L. WRI i 

